1. Cutsforth Support
  2. Shaft Grounding Assembly: Series 1
  3. Operations Manual – Shaft Grounding Assembly Series 1 – EZDP-2007

Installation Procedure

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Before installation, remove all original/OEM shaft grounding system equipment and clean the shaft of any surface defects, rust, and other contaminants. Review the documentation for the original/OEM Shaft Grounding System to plan its removal.

Installation Overview

The following figure shows the Shaft Grounding System installed: 

  • Panel assembly circle-a.png. The portion of the Shaft Grounding System that lays over the rope guide.

  • Attachment arm circle-b.png. An articulating arm assembly used to mount the Shaft Grounding Assembly to a secure structure.

  • Rope guide  circle-c.png. The portion of the Shaft Grounding System that lays over the shaft and holds the grounding and metering ropes.

  • Grounding rope kit circle-d.png. The portion of the Shaft Grounding System that ensure a continuous ground. 

  • Rope holders circle-e.png. The portion of the Shaft Grounding System that holds the ropes in place.

    EZDP-2007-OverviewMajorInstallSteps.png

Positioning the Panel Assembly

  1. Place the panel assembly circle-a.png and rope guide on the shaft circle-b.png.

  2. Orient the top face of the assembly so that is is relatively horizontal. Temporarily attach the panel assembly to the shaft using hands, clamps, tape, banding, wood frame, etc.

    EZDP-2007-PlacePanelAssy-1.png

Installing the Attachment Arm

Complete the steps in these sections to install the attachment arm:

  1. Attach the Connector Plate

  2. Mount the Adapter (for GE Units)

  3. Secure Position and Remove the Attachment Arm

  4. Weld Seams

Attach the Connector Plate

  1. Place the connector plates circle-a.png as shown. The location of the connector plate that mounts to the unit may vary.   

    • For GE units, a mounting bracket adapter is available for mounting to the OEM mounting location. Proceed to the Mount the Adapter section of this article..

    • For units not compatible with the GE mounting adapter, proceed to step 2 below.

    EZDP-2007-AttachConnectorPlate-1.png

  2. Drill four holes (5/16 in-18 tap x 3/4 in deep) for mounting to the unit using the Cutsforth connector plate as a template. 

  3. Attach the upper connector plate to the mounting location using the provided 5/16 in-18 x 3/4 in hex bolts and Nordlock washers.

Mount the Adapter (for GE Units)

Follow these steps to mount the adapter onto compatible GE OEM mounting locations. If the unit is not compatible with Cutsforth's GE mounting adapter, return to step 2 of Attach the Connector plate above.

  1. Remove the OEM mounting bolts and the existing OEM shim plate.

  2. Align a Cutsforth mounting bracket adapter circle-a.png on the OEM mounting holes. Replace the OEM bolts with new 3/8-16 x 2 in length bolts and Nordlock washers circle-b.png. Torque to 38 ft lbs.

    EZDP-2007-MountAdapterGEUnits-1.png

  3. Attach a connector plate circle-c.png to the mounting adapter and panel assembly using the provided 5/16 in-18 x 1/2 in length bolts and Nordlock washers.

    EZDP-2007-MountAdapterGEUnits-3.png

Secure Position and Remove the Attachment Arm

  1. Using a 5/32 in hex key wrench, tighten the three fasteners around the end of each elbow half (A) to 100 in lbs. Use the 5/32 in hex key wrench to tighten the center pivot fastener of each elbow to 70 ft lbs. Do not yet tighten the set screws between the elbows and attachment arm pipe.

  2. Remove the four hex bolts from the connector plate (B) and the two bolts from the attachment arm adapter connecting to the rope guide. Carefully remove the attachment arm assembly and Shaft Grounding Assembly, while taking care not to disturb the elbow assemblies, as this will cause misalignment.
    2035_6_2_5A.svg
    2035_6_2_5B.svg

Weld the Seams

The attachment arm is made of 300 series stainless steel. TIG welding is the preferred welding method. If a weld filler is needed, AWS E/ER 308, 308L, or 347 are acceptable.

NOTE:

The customer must provide a qualified welder to perform support arm welding.

  1. Begin by tack or stitch welding at the marks. The goal is a “stitch” or “fuse” weld. No additional welding material needs to be added at this time. The arm joints simply need to be locked in place by the tacks.

    CAUTION

    If the tacking step is overlooked and the welder commences to weld the seam, the attachment arm positioning will be compromised, resulting in a distorted arm, which is unusable and must be replaced.

  2. After tack welding, proceed to weld all of the seams as indicated with the red lines shown in the illustration below. Weld both ends and follow accepted welding practices to minimize distortions that would compromise proper alignments.

    EZDP-2007-WeldSeams-1.png

  3. Return the fully welded arm to the Cutsforth technician for final assembly on the generator.

Installing the Rope Guide

  1. Place the 1/16 in thick rope guide spacer circle-a.png on the shaft, and place the panel assembly circle-b.png back on the shaft, over the rope guide spacer.

    EZDP-2007-SecRopeGuide-1.png

  2. Install the welded attachment arm circle-c.png and check the gap between the shaft and the contact points on the panel assembly circle-b.png to make sure there are no misalignments. Torque all eight of the 5/16 in-18 x 1/2 in and 3/4 in length hex bolts with Nordlock washers circle-d.png to 240 in-lbs.

    EZDP-2007-SecRopeGuide-2.png

  3. Adjust the rope guide sections so that the contact points circle-e.png are against the rope guide spacer. Tighten all the 5/16 in-18 x 5/8 in length bolts on the rope guide starting closest to the panel assembly and then work around from there. Torque the 5/16 in-18 rope guide bolts circle-f.png to 220 in-lbs and the rope guide adjustment slot bolts circle-g.png to 240 in-lbs.

    EZDP-2007-SecRopeGuide-3.png

Installing the Grounding Wire

Complete the steps in these sections to install the grounding wire:

  1. Prepare the Grounding Wire and Twisted Pair Cables

  2. Route the Cables to the Remote Meter Point

  3. Complete a Shaft Grounding Continuity Test for the Shaft Grounding Assembly

  4. Complete a Shaft Grounding Continuity Test for the SCA

  5. Test Point Inspections

Prepare the Grounding Wire and Twisted Pair Cables

  1. Drill and tap a 5/16 in-18 hole 3/4 in deep in a suitable grounding location on the outside of the unit case circle-a.png to attach the grounding ring terminal circle-b.png (3/8 in dia. terminal).

    EZDP-2007-InstallGroundTwisterPairCables-1.png

  2. Cut the supplied grounding cable circle-c.png and 4 twisted pair cable circle-d.png to the appropriate length. Route the cables to the Remote Meter Point box as shown in Route the Cables to the Remote Meter Point below.

    EZDP-2007-InstallGroundTwisterPairCables-2.png

Route the Cables to the Remote Meter Point

  1. Remove four screws from the corners of the faceplate. Remove the faceplate to reveal the terminal connectors inside the Remote Meter Point box.

  2. Route cables from the Shaft Grounding Assembly to the terminal connectors. If your wiring diagram differs from this one, contact Cutsforth Engineering Support.

    EZDP-2007-RouteTheCables-1-a.png

    Part

    Description

    Part

    Description
    circle-a.png

    To and From Ground Current Test Point
    circle-b.png

    To Shaft Voltage Test Point
    circle-c.png

    To Meter Rope Test Point
    circle-d.png

    To Ground Rope Test Point
    circle-e.png

    Screw-down Jumper
    circle-f.png

    From Shaft Grounding Assembly
    circle-g.png

    To Unit Case Ground
    circle-h.png

    Black Wires & Drain from each Twisted Pair
    circle-i.png

    From Meter Rope
    circle-j.png

    From Meter Rope Wear Indicator
    circle-k.png

    From Ground Rope Wear Indicator

Only qualified electrical personnel should take measurements at the remote test points (circle-a.png = Ground Rope, circle-b.png = Meter Rope). For any of the test points located on the faceplate of the Remote Meter Point, use a hand-held volt meter, oscilloscope, clamp-on ammeter, or other appropriate testing device. Always follow proper electrical safety procedures. 

EZDP-2007-RouteTheCables-2.png

Complete a Shaft Grounding Continuity Test for the Shaft Grounding Assembly

Complete a shaft grounding continuity test before you connect the Shaft Grounding Assembly to the Remote Meter Point (ropes removed):

  1. With the Shaft Grounding Assembly installed, place the switch on the junction box assembly to "Run" mode.

  2. Strip all wires from the junction box assembly at the Remote Meter Point end and check that there is NO continuity between ANY wires.

  3. Check for continuity to determine which color wire is connected to the following:

    • Junction Box Assembly Metering Rope Holder Mount – Wire Color __________

    • Junction Box Assembly Metering Rope Wear Indicator Post – Wire Color __________

    • Junction Box Assembly Grounding Rope Wear Indicator Post – Wire Color __________

  4. Connect wires from the Junction Box Assembly to the Remote Meter Point.

  5. Check that there is continuity between the Remote Meter Point panel ground points and turbine ground.

  6. Check that there is continuity between the Remote Meter Point panel shaft voltage test point and the Shaft Grounding Assembly metering rope holder mount.

  7. Install the ropes in the Shaft Grounding Assembly.

  8. At the Remote Meter Point check that there is NO continuity between:

    • Grounding rope "wear indicator" test point and ground test point

    • Metering rope "wear indicator" and grounding test point

Complete a Shaft Grounding Continuity Test for the SCA

Complete a shaft grounding continuity test before you connect the SCA to the Remote Meter Point (ropes removed):

  1. Strip all wires from the SCA at the Remote Meter Point end and check that there is NO continuity between ANY wires.

  2. Check for continuity to determine which color wire is connected to:

    • SCA Metering Rope Holder Mount – Wire Color __________

    • SCA Metering Rope Wear Indicator Post – Wire Color __________

  3. Connect the case ground and SCA wires to the Remote Meter Point. If there is  no monitoring, run a small ground wire from the Remote Meter Point ground terminals to the unit case.

  4. At the Remote Meter Point panel confirm that there is continuity between the Remote Meter Point panel ground points and unit case ground.

  5. Check that there is continuity between the Remote Meter Point panel shaft voltage test point and the SCA rope holder mount.

  6. At the Remote Meter Point panel confirm that there is NO continuity between the shaft voltage test point and ground test point.

  7. Install ropes in the SCA.

  8. Confirm there is NO continuity between the rope "wear indicator" test point and ground test point.

Test Point Inspections

Shaft Voltage Test Point

The resulting voltage or waveform read at this point represents the shaft voltage at the metering rope location.

EZDP-2007-RouteTheCables-3.png

Ground Rope and Meter Rope (Wear Indicators)

Both of these test points connect to insulated conductors in the center of either the ground or metering ropes on the shaft.  

  • If a voltmeter indicates that a voltage is present (close to the shaft voltage read from the Shaft Voltage Test Point) then the insulated conductor has been worn through and the rope is in need of replacement.

  • If for any reason you are unsure if the voltage test is indicating a replacement is necessary, a second test method is to measure the resistance or continuity of the wear indicator line in reference to ground.

  • If there is infinite resistance or no continuity to ground then the insulation is still intact and the rope is less than 50% worn. Continuity, or little or no resistance, indicates the rope is worn to the point of needing replacement.

EZDP-2007-RouteTheCables-4.png

Ground Current Test Point

Use a clamp-on style current measuring device to test the current flowing to ground from the shaft. The panel indicates which end of the green ground conductor is connected to the shaft and which end is connected to the unit case ground.

EZDP-2007-RouteTheCables-5.png

Determining a Ground Conductor Termination Location

To most effectively ground your generator and minimize the effects of inductance on the 8 AWG ground conductor, it is imperative that the ground conductor take the shortest, most direct route from the Shaft Grounding Assembly to the unit case ground location.

NOTE:

When it comes to the ground conductor, shorter is always better. Cutsforth requires the total run length of the ground conductor (from the Shaft Grounding Assembly, to the Remote Meter Point, to unit case ground) to be under 15 ft. Cutsforth recommends the installation of a High-Frequency Drain on any installation with a ground run greater than 5 ft. The purpose of the High-Frequency Drain is to combat the effects of impedance on the ground wire. The High-Frequency Drain does this by dissipating the high-frequency transient voltage spikes through a short ground run with an inline 1-ohm resistor.

It is not necessary for the ground conductor to be grounded to an existing generator grounding pad. A generator grounding pad is often not the ideal ground location, as it requires a longer ground conductor run. The goal when choosing a grounding location is to electrically bond the shaft to the unit case ground. Cutsforth suggests drilling and tapping into the lower half of the unit case to create a grounding location closer to the Shaft Grounding Assembly. The location at which the ground wire will be terminated should have all paint removed and should be free of all contaminants in order to create a smooth, conductive surface.

After you determine the grounding location, you can install the Remote Meter Point directly between the grounding location and the Shaft Grounding Assembly. Structural steel and station ground are examples of unacceptable grounding locations.

Installing the Rope Grounding Kit

  1. Open the rope holder by pulling the handle circle-a.png  back, and remove the set screw circle-b.png using a 1/4 in hex key wrench.

    EZDP-2007-SecTheRope-1.png

  2. Insert the rope circle-c.png into the rope slot circle-d.png.

    EZDP-2007-SecTheRope-2.png

  3. Insert the rope terminal circle-e.png onto the terminal mount rib.

    EZDP-2007-SecTheRope-3a.png

  4. Secure the rope in position by tightening the set screw circle-b.png to 72-96 In-lbs (8-11 N-m).

    EZDP-2007-SecTheRope-4.png

Installing the Rope Holders

Complete the steps in these sections to install the rope holders:

  1. Install the Rope Holders

  2. Verify the Rope Holder Installation

Install the Rope Holders

  1. Start installing the rope holder circle-a.png into the grounding system by inserting the copper rope into the rope guide  circle-b.png.

    EZDP-2007-InsertRopeHolders-1.png

  2. Once the copper rope has been inserted into the rope guide, align the holder circle-a.png with the grooves on the sides of the mount circle-c.png and slide the holder into the mount.

    EZDP-2007-InsertRopeHolders-2.png

  3. Rotate and lock the handle circle-d.png into place while applying pressure toward the shaft. The position of the rope holder mount is set at the factory. Verify that the rope holder is approximately 1/8 in from the surface of the shaft.

    EZDP-2007-VerifyRopeHolderInstall-1.png

  4. Attach the female connector circle-e.png at the end of the grounding rope signal wire to the corresponding male banana jack circle-f.png.

    EZDP-2007-ConnectGroundRopeJunctBox-1.png

Verify the Rope Holder Installation

This table shows a correctly and an incorrectly installed rope holder:

Table 1. Correct/Incorrect Rope Holder Installation

Correct

Incorrect
EZDP-2007-VerifyRopeHolderInstall-3.png
EZDP-2007-VerifyRopeHolderInstall-2.png

This table shows a correctly and an incorrectly mounted rope holder:

Table 2. Correct/Incorrect Mounted Rope Holders

Correct

Incorrect

In this example, the terminal and holder are properly engaged:

EZDP-2007-VerifyRopeHolderInstall-6.png

In this example, the rope holder is not fully engaged:

EZDP-2007-VerifyRopeHolderInstall-4.png

In this example, the terminal is disengaged:

EZDP-2007-VerifyRopeHolderInstall-5.png

When you have completed the replacement, flip the switch located below the rope holders back to "Metering" or "Run" mode:

EZDP-2007-InstallNewGroundRopeKit-1.png
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